A fifth-wheel hitch is a common apparatus for coupling a trailer to a truck for towing. The fifth-wheel hitch is preferably positioned over or spaced forward of the rear axle of the truck. In trucks with short-beds, due to the shorter distance between the rear axle and the back of the cab, positioning the fifth-wheel hitch over or in front of the rear axle significantly limits the turning radius of the trailer without damaging the cab. To provide additional clearance between the cab and the trailer, a variety of moveable fifth-wheel hitch assemblies have been developed which permit sliding of the hitch rearward behind the rear axle in situations in which tight turns between the truck and the trailer are likely to be required.
For example, U.S. Pat. No. 7,871,096 to Colibert-Clarke et al. describes a displaceable fifth-wheel hitch assembly that includes a platform mounted in the bed of a truck with a pair of tracks mounted along each side thereof. A hitch assembly is slideably mounted between the tracks and includes a spring-biased locking pin that extends from the hitch assembly into holes aligned along the center of the platform. The locking pin is biased toward engagement with the platform by a spring disposed between a clip attached to the pin and a support member of the hitch assembly. A rod extends through a slotted flange extending from the platform and is coupled to the locking pin. The slotted flange acts as a fulcrum about which the rod can be pivoted to raise the locking pin and to allow the hitch assembly to move along the platform track. The rod can be engaged with a hook to maintain the locking pin in the raised position. Movement of the hitch assembly on the platform track can disengage the rod from the hook to allow the locking pin to engage the holes in the platform track and lock the hitch assembly in place.
U.S. Patent Publication No. 2011/0109061 to Peterson et al. describes a sliding hitch assembly mounted on a pair of elevated rails. A locking mechanism is provided that employs a cable actuated cam member and a pair of locking pins. One of the locking pins is associated with a forward position of the hitch assembly and the other is associated with a rearward position. A handle coupled to the cable is pivoted between a forward engagement position and a rearward engagement position to slide the cam member between a sidewall of the rails and a portion of the locking pins. The cam member thereby draws one locking pin out of engagement with the hitch assembly and allows the second locking pin to extend from the rail for engagement with the hitch assembly in the second position.
There remains a need in the art for a self-arming latching mechanism for a sliding-hitch assembly that is easily operable by a user. There is also a need for an automatic-arming latching mechanism with a locking feature that prevents disengagement of the latching mechanism. Some solutions employ spring biased members, but no mechanical engagement is provided to further prevent such disengagement. Additionally, a self-arming latching mechanism that is simple and compact for incorporation substantially within a base or hitch carriage would improve on prior designs.